Most transport network technologies such as Synchronous Digital Hierarchy (SDH), Optical Transport Network (OTN), Multi-Protocol Label Switching Transport Profile (MPLS-TP), and Provider Backbone Bridge-Traffic Engineering (PBB-TE) provide Operation and Maintenance (OAM) functions to monitor the health, or quality, of data plane connections. OAM functions can invoke data plane, control plane, and management plane actions such as protection switching, control plane controlled rerouting, management plane notifying alarms, and the like. Some technologies enable segment monitoring in which particular segments of a connection are monitored. However, the Generalized Multi-Protocol Label Switching (GMPLS) protocol discussed below does not support the configuration of segment-monitoring elements.
The GMPLS protocol is being developed as a common protocol set for various transport networks. The GMPLS signaling protocol is the Resource Reservation Protocol-Traffic Engineering (RSVP-TE), which provisions data plane connections. General attributes related to the end-to-end connections can be encoded in the signaling as well. For this purpose RFC 5420 specifies the Label Switching Protocol (LSP) Attributes object.
A typical use of the LSP Attributes object is to carry the OAM configuration parameters for the end-to-end connection. This solution enables the configuration of monitoring entities referred to as Maintenance Endpoints (MEPs) and Maintenance Intermediate Points (MIPs) and the endpoints of the connection. The GMPLS OAM configuration framework differentiates between technology-independent and technology-specific parts. The technology-independent part defines the OAM type and the desired OAM functionalities (for example, Connectivity Monitoring, delay measurement, and the like). The technology-specific part carries all the descriptors that are essential for configuring the OAM monitoring points.